Oxidation resistant lubricating oil composition



Patented Apr. 29, 1952 OXIDATION RESISTANT LU'BRICATING OIL COMPOSITIONRaymond L. Heinrich, Bay-town, Tera, assignor,

by mesne assignments, to: Standard Oil Development Company, Elizabeth,N. 1., a corporation of Delaware No Drawing. Application December 1,1950, Serial No. 198,723

5 Claims.

1 ,The present invention is directed to an improved lubricating oilcomposition which is resistant to oxidation. More particularly, theinvention is directed to a lubricating oil composibefore will ordinarilybe used in an amount in the range from 99.9% and 97.5% by weight with apreferred amount of about 98% by weight.

The invention will be further illustrated. A

tion including an olefinic polymer boiling in the 5 number ofcompositions were m up in which lubricating oil boiling range which issusceptible Gama-Z019 Was addefl to a mmerael 011 m 13116 to oxidationamount of 2% by weight and to octene-l polymer In accordance with thepresent invention an boiling in the lubnca'ting Oil boilipg range nolefinic polymer which is susceptible to oxidation g i by 33 g? $5 313?and which boils in the lubricating oil boiling 10 '3 563ml cm range andwhich has lubricating oil characterer .9 an c p i positions were thenoxidized by methods WhlCh istics is blended in an amount in the rangebetween 99 97 nd 97 57 b Wei ht with Garb Zola w1l1 be described furtherand the oxidized comt rodu' g g yhichghas 1e positions were then testedfor the per cent ind Ce p th i: 1 b Cy crease in viscosity at 210 F.,the neutralization owar 9 Ion e u f value, the carbon residue, the percent naphtha Ponent of the @m Fulthelmolei the insoluble and theoxidized compositions were Improved compssltlon does not m sludge alsoobserved for sludge formation. The results exposure to high temperatureoxidation as other of these tests along with, the amount of compositionsdo under those conditions ponents added to either the mineral oil or theThe carbaZOle p y in t e practice of the octane-l polymer are presentedin the following present invention is used in an amount no less table:

Table I Tests 011 Oxidized Oil Weight Inhibitor Percent LubricantPercent Inhibitor Increase, Ncut. Carbon Naphtlm Sludge Vis. ValueResidue Insoluble Formation 210F.

None MincralOil' 114 14.9 r2 None.- 0 Octene-l Polymerh. 247 11.6 3.30.3 Do. Carbazole 2.0 Mineral Oil 6 4.2 0.2 Moderate. Do 0.50cte11e-lPolymer." 52 10.6 1.4 0.1 None. Do 1.0 do 5.0 1.3 0.1 D0. D02.0 do 11 7.6 0.5 0.0 Do. lcridine 2.0 Mineral Oil 32 7.] 0.6 Light. Do2.0 Octene-l Polymer-.. 225 14.0 3.0 0.2 None.

1 Mineral White Oil, characteristics: 54.0 Vis. 210F., SSU, 82 viscosityindex. 2 Octchc-l Polymer, characteristics: 47.7 Vi's. 210F., SSU, 120viscosity index.

'oil polymers include the alpha olefins having about 5 to 10 carbonatoms in the molecule including pentene-l, hexene-l, heptene-l,octene-l, nonene-l and the higher members of the series mentioned. Theolefin polymer as mentioned subjected to severe oxidation conditions.

Anexamination of the data in the table shows that the composition inaccordance with the present invention including carbazole and octene-lpolymer was superior to other compositions. For example, it was superiorto the mineral oilcompositions containing carba'zole in that thecomposition of the present invention formed no observable amount ofsludge which is quite advantageous in the operation of an internalcombustion motor where the lubricating oii'is Furthermore, it will benoted that the data show the acridine', which is an effective inhibitorin mineral oil, fails in compositions including octene-l polymer as thehydrocarbon polymer therein. It may be concluded, therefore, that thecomposition of the present invention containing .carbazole gives amarkedly superior result over ;the prior art compositions. It will beespecially noted that the neutralization value, which is a measure ofthe organic acid content, was only 7.6 when using 2% by weight ofcarbazole in the composition of the present invention as compared with avalue of 14.0 when using 2% by weight of acridine in the octene-lpolymer. This reflects that much less oxidation occurred when using theacridine as inhibitor.

It is indeed surprising that acridine, which is a heterocyclic compoundclosely related to carbazole and which is known as an anti-oxidant forlubricating oil, had very adverse effects in compositions includingolefin polymer with respect to viscosity increase during oxidation. Itmay be seen that the composition of the present invention provides alubricating oil which is unsusceptible to oxidation and sludgeformation.

The oxidation test employed in the present invention is carried out asfollows in a 200 cc. glass three-necked round bottom flask. The centralneck of this flask is 5 cm. long and has an inside diameter of 3 cm. Theflask has two opposed side necks which are 6 cm. long and 1.5 cm. insidediameter, and aresituated at a 30 angle with the central neck,perpendicular to the surface of the spherical flask. The stirrer is aglass rod 0.5 cm. in diameter, entering the flask through a glass tubebearing held in place by a rubber stopper in the central neck, with twoglass blades 1.0 cm. long by 0.7 cm. wide welded to opposite sides ofthe bottom end of the glass rod at a 30 angle with the vertical. Thestirrer is driven by a 1750 R. P. M. motor connected to the stirrer by arubber tubing coupling. The blades of the stirrer are situated about 0.5cm. from the bottom of the flask and spin in such a direction that theirpropeller-like action circulates the oil to the bottom of the flask, upalong the sides of the flask, back to the center of the flask, and downto the stirrer blades again. A considerable amount of air is sucked downwith the descending oil and intimately contacted with it by the actionof the stirrer. A thermometer well 5 cm. long and 1.0 cm. insidediameter is situated in one side of the flask equidistant from the twoside arms. During the oxidation the flask is about two-thirds immersedin an oil bath maintained at 375 F. The temperature of the oil in theflask is usually 5 to 10 F. below the temperature of the oil bath.

Th oxidation-test is carried out in the specially constructed flask bystirring 100 cc. of the sample in the presence of air for sixteen hoursat 375 F. At the end of that time the flask is removed from the oil bathand tests obtained on the oxidized oil..

, h The neutralizationvalue which is used as -a method of test isdescribed in A. S. T. M. Standards for Petroleum Products and Lubricantsprepared by A. S. T. M. Committee D-2, November, 1948 and designatedTentative Method of Test for Neutralization Value (Acid and BaseNumbers) by Color Indicator Titration, A. S. T. M.

designation: 974-48T.

The carbazole making up a component of the present invention is onlysoluble to a small extent int-he olefinio polymer making upthe othercomthan 1% by weight remain in the composition as ponent. For example,carbazole will dissolve ine carbazole.

a dispersion or as a suspension. It is highly desirable that thecarbazole be in a dispersion or suspension in the olefl-nic polymerbecause it is believed that in this condition it is available to reactand inhibit the oxidation characteristics of the olefinic polymer whenthe composition is exposed to such conditions.

In order to bring about the desired dispersion or suspension of thecarbazole in the olefinic polymer, it may be desirable to add to thcomposition a suitable dispersing agent. Numerous compounds of this typeare Well known to the skilled worker and are typified by materials suchas alkali metal petroleum sulionates, ethylene oxide-fatty acid reactionproducts, zinc or copper naphthanates, alkali metal di-octyl succinatesulfonate, and the like. The desired amount of carbazole may also beadmixed with the octene-l polymer more readily by adding a solubilizingagent which will increase the solubility of the carbazole in theoctene-l polymer. Examples of suitable solubilizing agents include thecellosolves such as butyl or benzyl cellosolve, the mono-, di-, ortri-oleic, palmitic, or lactic glycerol esters, and the like.

The nature and objects of the present invention having been completelydescribed and illustrated, what I wish to claim as new and useful and tosecure by Letters Patent is:

' 1. An oxidation resistant lubricating oil composition which comprisesa polymer boiling in the lubricating oil boiling range of an alphaolefin having from 5 to 10 carbon atoms in the molecule, said polymerhaving lubricating oil properties and being susceptible to oxidation andnot less than 0.1 by weight of carbazole.

2. An oxidation resistant lubricating oil composition which comprises98% by weight of a polymer of octene-l boiling in the lubricating oilboiling range having lubricating oil properties and susceptible tooxidation and 2 by weight of carbazole.

3. An oxidation resistant lubricating oil composition which comprises alubricating oil polymer of an alpha olefin having from 5 to 10 carbonatoms in the molecule in an amount in the range between 99.9% and 97.5%by weight and carbazole in an amount in the range between 0.1% and 2.5%by Weight.

4. A composition in accordance with claim 3 in which the olefin isoctene-l.

5. An oxidation resistant lubricating oil com position which comprises apolymer of octene-l boiling in the lubricating oil boiling range havinglubricating oil properties and being susceptible to oxidation and notless than 0.1% by weight of RAYMOND LQHEINRICH REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS 'pgs. 604-610.

1. AN OXIDATION RESITANT LUBRICATING OIL COMPOSITION WHICH COMPRISES APOLYMER BOILING IN THE LUBRICATING OIL BOILING RANGE OF AN ALPHA OLEFINHAVING FROM 5 TO 10 CARBON ATOMS IN THE MOLECULE, SAID POLYMER HAVINGLUBRICATING OIL PROPERTIES AND BEING SUSCEPTIBLE TO OXIDATION AND NOTLESS THAN 0.1% BY WEIGHT OF CARBAZOLE.